Laser-induced ferroelectric domain engineering in LiNbO3crystals using an amorphous silicon overlayer

We report laser-induced poling inhibition and direct poling in lithium niobate crystals (LiNbO₃), covered with an amorphous silicon (a-Si) light-absorbing layer, using a visible (488 nm) continuous wave (c.w.) laser source. Our results show that the use of the a-Si overlayer produces deeper poling inhibited domains with minimum surface damage, as compared to previously reported UV laser writing experiments on uncoated crystals, thus increasing the applicability of this method in the production of ferroelectric domain engineered structures for nonlinear optical applications. The characteristics of the poling inhibited domains were investigated using differential etching and piezoresponse force microscopy.